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\(5^x+5^{x+2}=650;5^x.26=650;5^x=25;x=2\)
\(2^x+2^{x+3}=144;2^x.9=144;2^x=16;x=4\)
\(3^{x-1}+5.3^{x-1}=162;3^{x-1}.6=162;3^{x-1}=27;x=4\)
\(\left(x-5\right)^4=\left(x-5\right)^6\)
\(\rightarrow x-5=0\&x-5=1\) hoặc x - 5 = - 1
\(x-5=1;x=6;x-5=0;x=5;x-5=-1;x=4\)
\(\left(2^2:4\right).2^n=4;2^n=2^2;n=2\)
a) 8180 < 2790
b) 377 > 738
c) 536 < 1124
d) 291 < 535
Đúng thì k, sai thì thôi
Câu a:
81^80 và 27^90
81^80 = (3^4)^80 = 3^320
27^90 = (3^3)^90 = 3^270 < 3^320
81^80 > 27^90
\(A=1+6+6^2+...+6^{100}\)
\(6A=6+6^2+6^3+...+6^{101}\)
\(6A-A=\left(6+6^2+...+6^{101}\right)-\left(1+6+...+6^{100}\right)\)
\(5A=6^{101}-1\)
\(A=\frac{6^{101}-1}{5}\)
Hoàn toàn tương tự với các câu b) c)
\(A=1+6+6^2+6^3+...+6^{100}\)
\(6A=6+6^2+6^3+6^4+...+6^{101}\)
\(6A-A=\left(6+6^2+6^3+6^4+...+6^{101}\right)-\left(1+6+6^2+...+6^{100}\right)\)
\(5A=6^{101}-1\)
\(A=\frac{6^{101}-1}{5}\)
a ) số đối : -9 = 9 ; 17 = 17
b ) 63 = 216 ; 70 = 1
Bài 2 :
a) 42
b) 30
c) 3800
Bài 3 :
a) x = -31
b) x = 2
c) x = { -2 ;-1 ; 0 ;1;2;3;4 }
1/a.9;-17.
b.216;1
2/a.42;b.30;c.3800
3/a.x=-31;b.x=2;c.x=-2;-1;0;1;2;3;4.
1) Ta có: \(80-\left(5.4^2-4.2^3\right)\)
\(=80-\left(80-32\right)\)
\(=80-80+32\)
\(=32\)
2) \(60-\left[120-\left(42-33\right)^2\right]\)
\(=60-\left(120-9^2\right)\)
\(=60-120+81\)
\(=21\)
\(a,80-\left(5.4^2-4.2^3\right)\)
\(=80-\left(80-32\right)\)
\(=80-80+32\)
\(=32\)
\(b,60-\left[120-\left(42-33\right)^2\right]\)
\(=60-\left(120-9^2\right)\)
\(=60-39\)
\(=21\)
a,\(80-\left(5.4^2-4.2^3\right)\)
\(=80-\left(80-32\right)\)
\(=80-48\)
\(=32\)
b,\(60-\left[120-\left(42-33\right)^2\right]\)
\(=60-\left(120-81\right)\)
\(=60-39=21\)